1. Field of the Invention
The present invention is directed to an improved blood specimen collection system for collecting blood from humans and domestic animals. More particularly, the present invention is directed to a blood specimen collector cylinder which includes an ejector for the needle used during the collection, whereby the used needle can be ejected and discarded without being touched by human hands.
2. Brief Description of the Prior Art
Blood specimen collectors have been known in the art for a long time. More particularly, hypodermic syringes and needles have been used in the art for a long time to draw blood samples from humans and domestic animals.
Current hospital and clinical practice, however, requires the taking of blood specimens to occur rapidly and with inexpensive and readily disposable equipment. Ordinary hypodermic syringe and needle combinations do not meet these requirements well. The below-described state-of-the-art blood collecting system, on the other hand, permits rapid collection of blood specimen and uses a disposable needle and a collection tube in which the collected blood specimen is initially received and in which it may be stored until desired blood tests are performed.
More particularly, and still with reference to the state-of-the-art blood collecting system, for the drawing of blood specimen, a standard disposable needle assembly is placed into a threaded hole in the end wall of a hollow cylinder. The standard disposable needle assembly includes an externally extending hollow needle which is used to "stick" the patient to draw blood, and another needle extending inwardly into the interior of the hollow cylinder. The two needles are coaxial and are in fluid communication with one another. The collection tube is sealed at one end with a pierceable rubber or like septum. The collection tube is placed within the interior of the cylinder so that the septum is pierced by the inwardly extending needle. The patient's blood is then drawn into the collection tube through the needles without coming into contact with the hollow cylinder.
After the collection tube is withdrawn from the cylinder, the needle assembly is discarded. For safety reasons this requires placement of a protective cap or sheath on the externally extending needle, and subsequent twisting of the needle assembly to free it from the threaded hole. Because during its normal, intended usage the hollow cylinder does not come into contact with the patient's blood, therefore normally it is not discarded each time after a blood specimen has been collected.
Although the above-summarized prior art blood specimen collecting apparatus works well, it has a serious disadvantage in that it is necessary to manipulate and touch the needle assembly after the needle has been in contact with the patient's blood. Such manipulation unfortunately gives rise to the possibility of accidental wounding or pricking of a health care worker by the needle which has been used to collect blood capable of transmitting infectious diseases. It is well known in the art that certain serious, even fatal, diseases, such as hepatitis and AIDS, may be spread in this manner, that is, through accidental contact with infected blood.
In light of the foregoing, there is a definite need in the art for a blood sample collecting system or apparatus in which exposure to contaminated needles is minimized or eliminated. This need has not been met in the prior art, although various devices have been made in the hypodermic syringe and related arts for drawing blood specimens and for performing and facilitating the process of injection of drugs with hypodermic syringes.
U.S. Pat. No. 3,706,306 describes a blood specimen collecting apparatus substantially of the type which is referred to in the foregoing brief description as "state-of-the-art". U.S. Pat. No. 2,393,196 describes a hypodermic syringe apparatus having a pivotable end piece to which a needle can be mounted. U.S. Pat. Nos. 4,653,511; 4,710,170; 4,123,091; 2,376,436; 4,641,663; French Pat. No. 334,207; German Offenlegungsschrift No. 2451398 and German Offelegungsschrift No. 2815377 describe still further blood specimen collector and syringe type devices which comprise the background of the present invention.